Introduction

The Hafler GX2800 amplifiers are two rack height, two channel, fan-cooled professional power amplifiers suitable for use in the most demanding sound reinforcement and commercial sound installations. These amplifiers offer outstanding effi- ciency by means of three technologies: high-efficiency TRANS•nova Class-G circuitry, high-frequency switching power supplies, and constant power output/load impedance selection switches.

Technical Design Features

WHY A NEW AMPLIFIER TOPOLOGY?

Hafler TRANS•nova amplifiers, the recording studio reference, have a floating +/- power supply for each channel and a novel drive system covered by U.S. Patents 4,467,288 and 5,567,000. Our challenge was to convert this topology into a high efficiency design with minimal increase in complexity-yielding an amplifier of outstanding audio qualities, high effi- ciency and unprecedented value. TRANS•nova Class-G is that answer.

The most common high-efficiency (Class-H) methods raise the rail voltages going to the output devices for higher power levels. TRANS•nova Class G does not do this. Instead, it operates by forming a triplet or triplex of tracking signals: A, (A+V) and (A–V), where A is the raw audio output and +/– are the floating rails. The amplifier final output is selected to be at an appropriate voltage between (A+V) and (A–V) for each condition of the signal. The output voltage and current capability are each potentially doubled and the power potentially quadrupled–without having to increase the rail voltages fed to the devices. One or more patents are expected from this technology.

WHAT ELSE DISTINGUISHES THESE AMPLIFIERS?

Constant power into varying impedances. It takes twice as much current to develop a given wattage into 2Ω as it does into 8Ω—but only half the voltage. Many amplifiers quote a high output current at 2Ω but have an unpublished operating time measured in a handful of seconds—before thermal shutdown (hopefully) precludes thermal meltdown.

Our solution for this is selectable rail voltages for optimizing the amplifier to the load. This is impractical for conventional line-frequency supplies—and it comes at a cost for switching supplies. A full PWM design is needed, adding a coupled out- put inductor, a current-sense transformer and a current-mode controller IC. An impedance selector switch is also needed for each channel, simultaneously altering the rail voltage and the current limit. Each channel of the amplifier can be inde- pendently optimized for 2Ω, 4Ω, and 8Ω, useful in bi-amping and tri-amping, etc. Both 70 and 100 volt constant voltage line operation are possible. Instructions on the back of the amplifier explain the various options.

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Hafler GX2800CE manual Introduction, Technical Design Features, WHY a NEW Amplifier TOPOLOGY?
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GX2800, GX2800CE specifications

The Hafler GX2800CE and GX2800 are high-performance power amplifiers designed for audiophiles and professional sound reinforcement applications. Renowned for their reliability and audio fidelity, these models represent a seamless combination of innovative technologies and robust engineering that ensures impeccable sound quality.

One of the standout features of the Hafler GX2800 series is their high current output capability. This allows the amplifiers to drive a wide variety of loudspeakers, including those with demanding impedance requirements. With a power output of 280 watts per channel at 4 ohms, these amplifiers deliver sufficient power for large venues while maintaining clarity and dynamic range. The ability to handle low impedance loads without compromising performance is a hallmark of the Hafler brand.

The GX2800CE and GX2800 are equipped with Hafler's proprietary feedback technology, reducing distortion and enhancing overall sound quality. This technology ensures that the amplifiers perform well across the audio spectrum, allowing for rich, detailed sound reproduction. The low total harmonic distortion (THD) figures also contribute to a cleaner audio signal, ensuring that the listener experiences music as it was intended.

Another notable characteristic of the GX2800 series is its built-in protection circuitry. This includes short-circuit protection, thermal overload protection, and output DC protection, which work together to safeguard the amplifier and connected speakers during operation. The durable design of the chassis provides further reliability, suitable for both studio environments and live sound applications.

The amplifiers feature balanced XLR and unbalanced RCA inputs, providing versatility for various audio setups. Additionally, the rear panel includes binding post speaker outputs for secure connections to loudspeakers.

For those seeking a powerful and reliable amplifier that does not compromise on audio quality, the Hafler GX2800CE and GX2800 are exceptional choices. With their array of features designed to enhance performance and user experience, these amplifiers stand out in the competitive audio equipment market, making them ideal for both home and professional uses. Whether you are mixing in the studio or providing sound for a live performance, the Hafler GX2800CE and GX2800 will deliver exceptional results, making them a worthy investment for any audio enthusiast.
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